diff --git a/javacord-core/src/main/java/org/javacord/core/entity/channel/ServerThreadChannelImpl.java b/javacord-core/src/main/java/org/javacord/core/entity/channel/ServerThreadChannelImpl.java
index 7752b99c8..37efe6dc7 100644
--- a/javacord-core/src/main/java/org/javacord/core/entity/channel/ServerThreadChannelImpl.java
+++ b/javacord-core/src/main/java/org/javacord/core/entity/channel/ServerThreadChannelImpl.java
@@ -20,6 +20,7 @@
 import java.util.HashSet;
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * The implementation of {@link ServerThreadChannel}.
@@ -94,7 +95,7 @@ public ServerThreadChannelImpl(final DiscordApiImpl api, final ServerImpl server
         lastMessageId = data.hasNonNull("last_message_id") ? data.get("last_message_id").asLong() : 0;
         rateLimitPerUser = data.get("rate_limit_per_user").asInt(0);
 
-        members = new HashSet<>();
+        members = ConcurrentHashMap.newKeySet();
         if (data.hasNonNull("member")) {
             // If userId is not included, that means this came from a GUILD_CREATE event
             // This means the userId is the bot's and the thread id is from this thread
diff --git a/javacord-core/src/main/java/org/javacord/core/entity/channel/ServerVoiceChannelImpl.java b/javacord-core/src/main/java/org/javacord/core/entity/channel/ServerVoiceChannelImpl.java
index 4cb3788e8..ccf46fa8a 100644
--- a/javacord-core/src/main/java/org/javacord/core/entity/channel/ServerVoiceChannelImpl.java
+++ b/javacord-core/src/main/java/org/javacord/core/entity/channel/ServerVoiceChannelImpl.java
@@ -11,11 +11,11 @@
 import org.javacord.core.listener.channel.server.voice.InternalServerVoiceChannelAttachableListenerManager;
 
 import java.util.Collections;
-import java.util.HashSet;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.stream.Collectors;
 
 /**
@@ -37,7 +37,7 @@ public class ServerVoiceChannelImpl extends TextableRegularServerChannelImpl
     /**
      * The ids of the connected users of this server voice channel.
      */
-    private final Set<Long> connectedUsers = new HashSet<>();
+    private final Set<Long> connectedUsers = ConcurrentHashMap.newKeySet();
 
     /**
      * Creates a new server voice channel object.